1. Technical Field
The present disclosure relates to an observation system and a method of controlling the observation system.
2. Description of the Related Art
In culturing cells, if it is possible to start observation concurrently with emergence of a cell mass, which is formed by gathering of a plurality of cells, and to conduct the observation sequentially in chronological order, this can be a promising technique, for example, for supporting regenerative medicine. Such observation of cells is conducted when replenishment or replacement of culture fluid in a culture container is required during cell culture, by using a microscope or the like, and images are picked up as needed.
However, observation of cells using a microscope requires much expense in time and effort. For example, in order to identify a cell mass having emerged in a container, first, the whole container needs to be observed visually or by using a microscope, and further, a growing state of the individual cell mass needs to be observed under magnification, for example, by replacing an objective lens. In micro observation, a narrow field of view causes difficulty in searching a target cell mass, and further causes difficulty in adjusting the cell mass to the field of view. When observing cells, it is preferable to conduct time-lapse observation in which a long-term change is observed from a time of the emergence of the cell mass to a time of the completion of growth thereof for every predetermined time period. Since, immediately after seeding of the cell, the cell mass cannot be observed visually, by using a low-magnification microscope, or the like, an observation position needs to be searched and reset several days later.
Further, in the observation that is conducted when culture fluid in a culture container is replenished or replaced usually once in one to three days, it is difficult to conduct observation from a time of the emergence of a cell mass, and thus a technique that is capable of observing a cell mass from the time of the emergence thereof is in high demand.
In order to perform such observation of the cell mass in an appropriate manner, it is important to illuminate the cell mass in the container with appropriate brightness. In various optical devices, techniques for displaying an object with appropriate brightness have been developed (see, e.g., Japanese Laid-Open Patent Publication Nos. 2001-188177 and 2002-214697).
However, the container used for the culturing a cell mass and the like comes in various sizes, and thus it is not easy to have appropriate brightness at the time of observation, whatever container may be used. For example, a ring illumination having a light source provided in a ring shape may be used to reduce uneven illuminance between a center part and a peripheral part of a culture surface, but even in this case, when the containers of different sizes are used, it is difficult to prevent occurrence of uneven illuminance.
Whereas, change in size and the like of the ring illumination according to the size of the container on a case-by-case basis causes an increase in cost, scale of the device, and the like.
Therefore, such a technique is in demand that makes it possible to illuminate the container uniformly with appropriate brightness, even if the sizes of the containers containing observation targets are vary, when observation of cells and the like is conducted.
The present disclosure makes it possible to illuminate, uniformly with proper brightness, containers of various sizes containing observation targets such as cells, bacteria, and microorganisms.